I practice good behavior and, eventually, it is larger/happens more often than the bad. With eye contact, I start with store clerks and other people I just happen to meet that aren't "important" to me. With them behind counters, it might be a little easier for you to concentrate on doing that since you cannot see private parts. Maybe pick male clerks so you cannot look at boobs, etc. :-) It's basically a habit you got into out of fear/distaste with your grandparents. You might benefit from seeing a therapist to discuss the problem but you could also just see if you could replace the behavior with another. Maybe start a "button" collection and tell yourself to stare at people's top button on their blouse or shirt? And/or a teeshirt collection (for those not formally dressed in a shirt/blouse); make a habit of telling people you meet that you "like" their teeshirt or otherwise commenting on it and starting a conversation?